I don't know if I'm right or not but I think that mixers like Thormixer and other Jambler partner might have a mechanism to block all those addresses that are liked with groups like Lazarus in order to protect themselves from authorities. They might have blacklisted those groups wallet addresses.
I'm pretty sure that people behind groups like Lazarus know very well how to get around the use of blacklisted addresses. It's a bit unbelievable to me when I see claims that some Bitcoin address belongs to hackers and anyone can see how much balance is on their addresses. So, they are capable of hacking a system and withdrawing huge amounts of Bitcoin, but they struggle a lot to hide those coins.
Am I the only one who finds this unusual?